Definition: Idiopathic juvenile polyarthritis includes a group of inflammatory diseases that affect at least five joints, either from onset or within the first six months of the disease course in children under 16 years of age. Diagnosis is arrived at by elimination. Besides malignant disease, always to be considered as a differential diagnosis, idiopathic juvenile polyarthritis can be divided into rheumatoid factor (RF)-positive and RF-negative polyarthritis and extended forms of oligoarthritis. RF-NEGATIVE POLYARTHRITIS: Antinuclear antibody (ANA)-positive polyarthritis must be distinguished from extended forms of oligoarthritis which are also ANA-positive. ANA-positive polyarthritis generally begins early, at the age of 2 or 3 years, predominantly in girls. Characteristic torpid uveitis is frequent, requiring regular systematic screening. Joints are minimally painful with symmetrical involvement, usually of the knees and wrists. Progressive joint destruction and/or growth disorders are common. The disease progresses by acute episodes. Nonsteroidal antiinflammatory drugs are used, associated with a specific treatment and local care as needed. General corticosteroids may be required in certain cases but should be avoided if possible.
Seronegative forms: Certain patients have no detectable antibodies. These patients generally have fewer ocular problems and less severe joint disease. The treatment is the same as in ANA-positive forms. RF-positive polyarthritis: RF-positive polyarthritis is exceptional and occurs early in young girls.
Specialized care: Irrespective of the type of disease, all children with idiopathic juvenile polyarthritis require multidisciplinary specialized care for their chronic and severe, potentially invalidating disease.